Reproductive decline has been a challenge facing the dairy industry worldwide for several decades and has typically been blamed on selection for increased milk production [Sheldon I M, Dobson H. Reproductive challenges facing the cattle industry at the beginning of the 21st century. Reprod Suppl. 2003; 61:1-13]. In the United States alone, first service to conception rate has declined from approximately 65% in 1951 to 40% in 1996 [Butler W R. Review: effect of protein nutrition on ovarian and uterine physiology in dairy cattle. J Dairy Sci. 1998; 81:2533-2539], while the number of services per conception has increased from approximately 1.8 in 1970 to approximately 3 in 2000 [Lucy M C. Reproductive loss in high-producing dairy cattle: where will it end? J Dairy Sci. 2001; 84:1277-1293]. It was reported that during 1976 to 1978, the average number of days open (days between calving and the subsequent conception) was 122 days for Jerseys and 124 days for Holsteins [Washburn S P, Silvia W J, Brown C H, McDaniel B T, McAllister A J. Trends in reproductive performance in Southeastern Holstein and Jersey DHI herds. J Dairy Sci. 2002; 85:244-251]. However, days open increased to 152 days for Jerseys and 168 days for Holsteins by 1997 to 1999. In the United Kingdom, the conception rate to first service of dairy cows has declined from 65.4% (1975-82) to 44.3% (1995-98) at a rate of approximately 1% per year [Royal M D, Darwash A O, Flint A P, Webb R, Woolliams J A, Lamming G E. Declining fertility in dairy cattle: changes in traditional and endocrine parameters of fertility. Anim Sci 2000; 70:487-502]. Equivalent decreases in first—service conception rate have been also observed in dairy cattle in Ireland [Roche J F, Mackey D, Diskin M D. Reproductive management of postpartum cows. Anim Reprod Sci 2000; 61:703-712] and Australia [Macmillan K L, Lean I J, Westwood C T. The effects of lactation on the fertility of dairy cows. Aust Vet J 1996; 73:141-147]. Understanding the genetic causes of reduced fertility is essential to halt the currently observed fertility decline in lactating dairy cows.
To address the difficulties of achieving desired levels of reproductive performance in today's milking herds, a new fertility trait, the daughter pregnancy rate (DPR) was introduced as an indicator of sire fertility for genetic selection [VanRaden P M, Sanders A H, Tooker M E, Miller R H, Norman H D, Kuhn M T, Wiggans G R. Development of a national genetic evaluation for cow fertility. Dairy Sci 2004; 87:2285-2292]. Pregnancy rate is defined as the percentage of nonpregnant cows that become pregnant during each 21-day period. In fact, data for calculating DPR are taken from reported days open, which are calculated as date pregnant minus previous calving date. Date pregnant is determined from last reported breeding or from subsequent calving minus expected gestation length. For calculation of genetic evaluations, days open are converted to daughter pregnancy rate by the linear transformation of pregnancy rate=0.25 (233-days open). Evaluations are expressed as predicted transmitting ability (PTA) for DPR, and calculations are generated as a direct result of a bull's daughters performance [VanRaden P M, Sanders A H, Tooker M E, Miller R H, Norman H D, Kuhn M T, Wiggans G R. Development of a national genetic evaluation for cow fertility. Dairy Sci 2004; 87:2285-2292]. In addition, cow fertility is a major component of productive life (PL) or longevity. Improving both DPR and PL would lead to the increased productivity and profitability to the dairy industry.
Calpastatin (CAST) is an endogenous protease inhibitor that specifically acts on two Ca2+-independent proteases, μ-calpain and m-calpain by binding and forming an inactive complex. CAST is widely expressed in mammalian cells and tissues, including those related to reproduction. For example, the CAST gene is expressed in the human pituitary gland [Kitahara A, Takano E, Ontsuki H, Kirihata Y, Yamagata Y, Knaagi R, Murachi T. Reversed distribution of calpains and calpastatin in human pituitary gland and selective localization of calpastatin in adrenocorticotropin-producing cells as demonstrated by immunohistochemistry. J Clin Endocrinol Metab 1986; 63:343-348], the human placenta [Thompson V F, Saldana S, Cong J, Luedke D M, Goll D E. The calpain system in human placenta. Life Sci 2002; 70:2493-508], the human oocyte [Ben-Aharon I, Ben-Yosef D, Amit A, Shalgi R. Expression and immunolocalization of the calpain-calpastatin system in the human oocyte. Fertil Steril 2005; 83:1807-1813], the bovine corpus luteum [Orwig K E, Bertrand J E, Ou B R, Forsberg N E, Stormshak F. Involvement of protein kinase-C, calpains, and calpastatin in prostaglandin F2 alpha-induced oxytocin secretion from the bovine corpus luteum. Endocrinology 1994; 134:78-83], as well as during spermatogenesis in the testes of humans [Liang Z G, O'Hem P A, Yavetz B, Yavetz H, Goldberg E. Human testis cDNAs identified by sera from infertile patients: a molecular biological approach to immunocontraceptive development. Reprod Fertil Dev 1994; 6:297-305; Li S, Liang Z G, Wang G Y, Yavetz B, Kim E D, Goldberg E. Molecular cloning and characterization of functional domains of a human testis-specific isoform of calpastatin. Biol Reprod 2000; 63:172-178 and Wei S G, Wang L F, Miao S Y, Zong S D, Koide S S. Expression of the calpastatin gene segment during spermiogenesis in human testis: an in situ hybridization study. Arch Androl 1995; 34:9-12.], mice [Li S, Goldberg E. A novel N-terminal domain directs membrane localization of mouse testis-specific calpastatin. Biol Reprod 2000; 63:1594-1600] and rabbits [Wang L F, Miao S Y, Yan Y C, Li Y H, Zong C, Koide S S. Expression of a sperm protein gene during spermatogenesis in mammalian testis: an in situ hybridization study. Mol Reprod Dev 1990; 26:1-5]. Interestingly, the CAST protein was identified as one of the target antigens for anti-sperm antibodies found in infertile women [Koide S S, Wang L, Kamada M. Antisperm antibodies associated with infertility: properties and encoding genes of target antigens. Proc Soc Exp Biol Med 2000; 224:123-132]. In vivo, CAST anti-BS-17 antibodies can block the fertilizing capacity of mouse sperm to fertilize ova by significantly reducing the numbers of developing embryos [Koide S S, Wang L, Kamada M. Antisperm antibodies associated with infertility: properties and encoding genes of target antigens. Proc Soc Exp Biol Med 2000; 224:123-132]. All these results indicate that the CAST gene plays an important role in reproductive biology.
The primary structure of the calpastatin amino-acid sequence includes four internally repetitive domains (Domains 1-4) and one non-homologous domain at the amino-terminal end (Domain L) [Murachi T. Calpain and calpastatin. Rinsho Byori 1990; 38:337-346]. However, a new N-terminal peptide domain, named domain XL, was identified in cattle [Cong M, Thompson V F, Goll D E, Antin P B. The bovine calpastatin gene promoter and a new N-terminal region of the protein are targets for cAMP-dependent protein kinase activity. J Biol Chem 1998; 273:660-666]. This “XL” region contains sixty-eight amino acids, but shares no homology with other regions of calpastatin or with any known proteins. In vivo experiments showed that the “XL” region is a substrate for phosphorylation by protein kinase [Cong M, Thompson V F, Goll D E, Antin P B. The bovine calpastatin gene promoter and a new N-terminal region of the protein are targets for cAMP-dependent protein kinase activity. J Biol Chem 1998; 273:660-666].
It remains advantageous to provide further SNPs/STRs that may more accurately predict the fertility and longevity phenotypes of an animal and also a business method that provides for increased production efficiencies in livestock cattle, as well as providing access to various records of the animals and allows comparisons with expected or desired goals with regard to the quality and quantity of animals produced.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.